SPRING, Texas — A fight, possibly gang related, broke out at a suburban Houston high school Wednesday, leaving one student dead of stab wounds and three other students injured, the authorities said.

The confrontation unfolded shortly after 7 a.m., a few minutes before classes began at Spring High School, one of the largest high schools in Harris County. The 3,500-student campus, next to Interstate 45 about 20 miles north of downtown Houston, was locked down throughout the morning. After the authorities determined that the school was secure, they kept students in classrooms to interview potential witnesses.

Adrian Garcia, the Harris County sheriff, said the confrontation might have been gang-related, and investigators were questioning three people. He said that no arrests had been made, but that all of the people investigators were interested in were in custody.